Flutter Interview Questions and Answers

 1. What is Flutter?

Flutter is cross platform development toolkit by Google, which helps to deploy on multiple platform with single code base and achieve great UI Quickely.

or

 Flutter Flutter, an open-source mobile app development SDK, is created by Google. It is used for creating high-quality, cross-platform native interfaces for both iOS and Android platforms. Flutter uses Dart to help mobile app developers build native interfaces. Dart is one of the new programming languages. With the flexibility it has in development, it has become one of the broadly used mobile app development technologies. Some of the apps developed using Flutter are Google Ads, Reflectly, Xianyu by Alibaba, and many more. 

Read more at: https://yourstory.com/mystory/top-mobile-app-development-technologies-2020

2. What are the types of widgets in Flutter?

Mainly, there are two types of widgets, StateFull Widgets and Stateless Widgets.

3. What is the difference between  StateFullWidget and StatelessWidget?

StateFull widgets holds State of the widget and can be rebuilt when State changes.

whereas, Stateless widgets are builds only when it is created or parent changes.

or

what is mutable and immutable ? 

Mutable means changeable, you can change property of mutable variable or function at run time. In other world we can say it’s value is dynamic.

Immutable mean properly of the variable or function will not be change after set it once. In other world we can say it’s value is Static.

For StatelessWidget - It’s static, This widget will not be change after run time.

StatefulWidget - It’s dynamic, This widget will change any time where you want. 

So If any API will call and JSON data are coming and You want it to display on ListView then you must use with StatefulWidget. Any operation if you want to display on run time that will be done by StatefulWidget.

StatelessWidget - Work with static data. If you render any static list that will not be change any time that you can go with this widget.

Stateful widget are widget that manage state that work with state that were update variables 

and update the view according to those variables or just show something dynamically in your view according to some data in your component 

donot manage state they just get some data through

the props and show the view accordingly so 

4. How to access screen size in Flutter?

we can access screen size and other properties like pixel density, aspect ratio etc

with help of MediaQuery. syntax MediaQuery.of(context).size.width

5. How do we access native features of the Platforms?

eg. Battery Level

Basic Req

Familiarity with OOP design principles

UI : Material design, Material animations, Custom components, User Interaction(touches, gestures)

Core : Dart, Multithreading, FlutterPub, Rx Dart, Job Queue

Communication & Networking : HTTP, REST, Dio, Cached Network Image, Firebase, Socket, JSON, XML, SMS, Bluetooth, NFC

Social: Facebook, Twitter, Linkedin, Instagram, Google+

Google Services: Firebase, Analytics, Maps, Location, Cloud Messaging, Mobile Ads

Push Notifications

Hardware and Media: GPS, Playing Audio/Video, Accelerometer, Camera

Persisting Data: SharedPreferences, Files, SQflite, Backup and Sharing data

Experience with Offline Storage, Threading, and Performance Tuning

Interacting with System: Notifications, Alarm Manager, Timed and Periodic Tasks, Persistent Background Operations, Contacts, Calendar

6. What is AppBar Widget?

AppBar widget or top App Bars is a collection of widget located at the top of the app, for wrapping our app’s title, icon, and action link.